Siphon breaker and backflow preventer



was-K I A March 24, 1959 s. DOLENGA 2,878,826

SIPHON BREAKER AND BACKFLOW PREVENTER Fiied Aug. 10, 1956 INVENTOR. 6779/1445? 0045/1 65 sink to prevent back-flow and siphoning of waste water from the sink to the appliance.

Dishwashers usually have a pump that conducts the waste water from the well of the dishwasher to the drain of an adjacently positioned sink. The outlet of the dishwasher pump is sometimes connected with the sink drain by a continuous conduit. More often, however, the outlet of the pump is connected to the sink drain by means of a conduit having a vacuum break therein. This vacuum break is conventionally in the form of a funnel disposed at a level above the top of the sink and discharging into the pump outlet line and a second conduit from the sink drain and discharging downwardly into the funnel.

These arrangements produce considerable difficulty when the sink drain becomes plugged. If the sink drain becomes plugged and the dishwasher pump is connected by a continuous conduit with the drain, waste water in the sink will flow backwardly either because of the pressure head of the water in the sink or by reason of siphoning into the well of the dishwasher. This not only produces a messy and unsanitary condition; but if the housewife is not aware of the fact that the drain is plugged, it

Fig. 3 is a view similar to Fig. 1 and showing the maner in which the fitting of this invention may be arranged in a dishwasher outlet line connected with a sink drain in which a garbage disposal unit is not incorporated.

Referring to the drawings, a sink is shown at and a dishwasher at 12. The sink has a garbage disposal unit 14 connected with the outlet thereof, and the outlet of the garbage disposal unit connects with a drain 16. In the dishwasher 12, there is a waste water well 18 to which is connected a pump 20 for discharging the water there in into drain 16. The outlet pump 20 has a conduit 22 3 that connects with a conduit 24 extending to an inlet tap 26 on the garbage disposal unit 14. Between conduits 22 and 24, there is arranged the fitting 28 of the present invention. The fitting 28 is preferably located adjacent the upper portion of dishwasher 12. Another conduit 30 extends upwardly from waste water well 18 to adjacent fitting 28 and is provided with a funnel-shaped fitting 32.

at its upper end. The arrangement shown in Fig. 3 is generally the same as that shown in Fig. 1 with the exception, however, that in the arrangement shown in Fig.

.;; 3, the sink is not provided with a garbage disposal unit and conduit 24 connects with the outlet 34 of sink 1i).

Referring now to Fig. 2, the details of fitting 28 are illustrated. This fitting includes an outer sleeve 36 having an externally enlarged end 38. Over the end 38 is .Ltelescoped an end connection member 40 to which the can also produce overflowing of the waste water in the' dishwasher well.

Where the discharge conduit from the dishwasher pump to the. drain is provided with a vacuum break such as described above and the drain becomes plugged, a likewise serious condition results. Under these conditions, if it is attempted to dislodge the material clogging the drain by applying pressure to the sink outlet either by means of a plunger or by means of water pressure from the faucet of the sink, the water in the drain willbe discharged through the vacuum break and produce a very messy condition either under the sink or above the sink depending on where the vacuum break is located. In the case of sinks provided with garbage disposal units, the seriousness of the situation is even worse since if the drain is clogged and the garbage disposal unit is energized, the ground refuse will be pumped either into the well of the dishwasher or, in the case of an arrangement where a vacuum break is provided in the line, out through the vacuum break.

It is an object of this invention to provide a fitting adapted to be connected into the discharge line between a dishwasher and a sink drain which eliminates entirely the foregoing difficulties.

The device of the present invention is also designed and adapted to be arranged such that should the drain of the sink become plugged, the user will be warned of this condition before it has progressed too far.

In the drawings: I

Fig. l is a generally diagrammatic view showing the fitting of this invention arranged in a discharge line between the pump of a dishwasher and a sink drain which incorporates'a garbage disposal unit.

Fig. 2 is a longitudinal sectional view through the fitting of this invention.

conduit 24 is connected. An 0-ring 42 is provided for forming a fluid tight connection between the enlarged end 38 of sleeve 36 and member 40. Member 40 is arranged to be held in place on sleeve 36 by screws 43. The enlarged end of sleeve 36 has an outlet opening 44 that is inclined to the radial plane of sleeve 36. This inclination may be on the order of about 10. Around the edge of opening 44, there is provided a sealing gasket 46 which may, for example, be formed as a rubber O-ring. Outlet 44 is normally closed by a flapper check valve 48 which is hinged to swing about the pivot 50. Fitting 28 is arranged so that pivot 50 is at the top side of the fitting when installed whereby valve 48 normally gravitates to the closed position seating on gasket 46. The opposite end of fitting 28, that is, the end that connects with conduit 22, is internally threaded as at 52 to threadedly receive a venturi member 54. Venturi 54 is fashioned as a funnel-shaped conduit having its outlet end 56 disposed directly adjacent and generally concentric with the outlet opening 44 of sleeve 36. At one side of sleeve 36, there is provided a short depending conduit 58 that is arranged to discharge into funnel 32 at the upper end of line 30.

The fitting shown in Fig. 2, when installed in the maner illustrated in Figs. 1 or 3 in the discharge line of the dishwasher, is adapted to eliminate the difficulties re- 1 ferred to above in connection with clogged sink drains.

When the pump 20 is operated to discharge the water from the waste water well 18 of the dishwasher, the waste water is caused to flow under pressure upwardly to pipe 22 and through the venturi 54. The water issuing from,

the outlet 56 of venturi 54 impinges against the valve 48 to open the valve and cause the water to be discharged through conduit 24 and to the drain 16 through the garbage disposal unit 14. I have found that the velocity 7 of the water flowing through venturi 54 produces a slight Now, if it should happen that drain 16 becomes clogged for some reason and the housewife is not aware of this condition and turns on the dishwasher, on the discharge cycle pump 20 would operate to discharge water through venturi 54 and this water would simply flow into sink 10.

Patented Mar. 24, 1959 As soon as the pump 20 stopped operating, flapper valve tively prevent the waste water from flowing back into the well 18 of the dishwater. It is conceivable, however, that small particles of food, etc. might become lodged between flapper valve 48 and its gasket seat 46 to thereby prevent valve 48 from completely closing outlet 44. Under these circumstances, some of the water in sink might slowly flow back into sleeve 36 and this water will drain out of the fittting through tube 58 and back into well 18 through conduit 30. However, this drainage back into well 18 will occur only very slowly as permittedby the extent to which valve 48 remains open and only until the level of water in sink 10 falls to the elevation of fitting 28. The arrangement of tube 58 with conduit 30 provides a vacuum break in the line between sink 10 and well 18; and therefore, there will be no siphoning action. If, while drain 16 is in the clogged condition, the garbage disposal unit 14 is turned on, water under pressure will back up in line 24 and firmly seat valve 48- on gasket 46. The garbage disposal unit will simply pump against the head of pressure, but none of this water will flow back into waste water well 18.

conduit of a dishwasher eflectively prevents any serious not necessary that the fitting be located above the upper edge of the sink well which is normally necessary where the vacuum break in the outlet line of a conventional dishwasher hook-up has to be placed. It will also be appreciated that with the arrangement shown herein, should the sink drain become clogged, this fact will soon be indicated to the housewife because water will either accumulate in the sink when the dishwasher is turned on or the water level in the sink will not recede when the garbage disposal unit is operated. In addition, it will be observed that the provision of the fitting 28 in the pump discharge line in no way complicates the installation.

I claim:

1. An anti-siphon and backflow preventing fitting for use in a waste water line to a sink drain from an appliance having a pump discharge, said fitting comprising a body member having an inlet at one end and an outlet at the other end, a normally closed check valve Within said body member spaced intermediate the inlet and the outlet to prevent the flow of water from the outlet tothe inlet when closed, a tubular member within said body member and extending from adjacent said inlet toward said outlet, said tubular member having an inlet communicating with the inlet of said body member such that all the fluid entering said body member inlet is caused to flow through said tubular member and having an outlet aligned axially with said check valve, the outlet end portion of said tubular member being of smaller cross section than the adjacent portion of said body member and being spaced relatively closely adjacent to said check valve so that the water stream issuing therefrom impinges against said check valve to open the same, said body member having a vent opening therein spaced between the inlet end of the tubular member and the outlet ofsaid tubular member, said vent opening communicating freely at all times with the interior portion of said body between the inlet thereof and said check valve.

2. The combination called for in claim 1 wherein said check valve. comprises means within said body forming a valve seat lying in a generally vertical plane and a flapper, valve pivotally supported within the body and responsive to gravity to close with said valve seat.

3. The combination called for in claim-1 wherein said body is of tubular shape and is threaded at the portion thereof adjacent its inlet end, said tubular member comprising a sleeve threaded at its inlet end, the inlet end of said sleeve being in threaded engagement with the threaded portion of said body for axial adjustment to permit variation in the spacing between the outlet end of the sleeve and said check valve.

4. The combination called for in claim 1 wherein said 1 sleeve comprises a venturi.

v Thus, it will be seen that the fitting of this invention and the manner in which it is connected with the outlet 5. In an arrangement including a sink having a drain, a washing appliance having a pump outlet for discharging waste water from the appliance and a conduit extending from the pump outlet to the drain, the improvement which comprises an in-the-l-ine fitting in said conduit comprising a body member having an inlet at one end connected with the portion of the conduit extending to the pump outlet and an outlet connected with the portion of the conduit connected with said sink drain, a normally closed check valve within said body member spaced intermediate said inlet and said outlet, a tubular member within said body member having an inlet and an outlet, the inlet of said tubular member communicating with the inlet of said body member such that all the fluid entering said body member inlet is caused to flow through said tubular member and the outlet of said tubular member being aligned axially with said check valve, the outlet end portion of said tubular member being of smaller cross section than the adjacent portion of said body member and being spaced suffi'ciently close to said check valve so that the water stream issuing therefrom impinges against said check valve to open the same, said body having a vent opening therein spaced between the inlet of said body and the outlet of said tubular member, said opening communicating freely at all times with the interior portion of said body between the inlet thereof and said check valve and a conduit extending from said vent opening to the washing appliance on the inlet side of the pump, said last mentioned conduit having an opening therein communicating with the atmosphere.

6. The combination called for in claim 5 wherein said tubular member is disposed with its longitudinal axis in a generally horizontal position above said appliance, said check valve comprising means within said body member forming a valve seat disposed in a generally vertical plane and a flapper valve pivotally supported within said body member and responsive to gravity to close with said valve seat.

7. The combination called for in claim 6 wherein said vent opening is located on said body member at one] side of said tubular member, said last mentioned conduit extending downwardly from said vent opening to the appliance.

8. The combination called for in claim 6 wherein said tubular member comprises a sleeve having a frustoconically shaped outlet end portion which is spaced from the wall of said body member, said vent opening communicating with the interior of said body member into the space between the wall of said body member and the frusto-conically shaped portion of said sleeve.

9. The combination called for in claim 8 wherein said sleeve is threadedly supported within said body member for axial adjustment whereby to permit variation in the spacing between the outlet end of said sleeve and said check valve.

References Cited in the file of this patent UNITED STATES PATENTS 2,131,430 Dobrick Sept. 27, 1938 2,516,578 Kreiner July 25, 1950 2,552,398 Briggs May 8, 1951. 2,580,199 Schmid Dec. 25, 1951 2,691,986 Kirby Oct. 19, 1954 FOREIGN PATENTS 184,238 Switzerland Aug. 1, 1936 

